Cow's Milk Allergy Algorithm

Safety

Red Flags — Exclude anaphylaxis, failure to thrive, FPIES

Done

Urgent exclusion of life-threatening allergic reactions and severe malnutrition.

Anaphylaxis features Acute onset facial/lip swelling, wheeze, stridor, hypotension, collapse within minutes of milk exposure → 999 IM adrenaline 150 mcg (<6 months) or 300 mcg (6m-6yrs)

Severe faltering growth Weight <2nd centile, crossing 2+ centile lines, no weight gain 2+ weeks → Same-day paediatric assessment (malnutrition, neglect, metabolic disease)

FPIES presentation Profuse vomiting 2-4 hours after milk (not immediate), lethargy, pallor, hypotension, hypothermia → 999 (Food Protein-Induced Enterocolitis Syndrome — can cause shock)

Haematemesis / melaena Blood in vomit or stools, coffee-ground vomit, black tarry stools → Same-day paediatrics (severe CMPA enteropathy, erosive disease)

Severe eczema + infection Widespread infected eczema, fever, systemically unwell → Same-day (eczema herpeticum risk, sepsis)

Dehydration Sunken fontanelle, reduced urine output, dry mucous membranes, lethargy → Same-day assessment (severe gastroenteritis, FPIES)

Respiratory distress Wheeze, stridor, increased work of breathing within 2 hours of feed → 999 (anaphylaxis, severe IgE-mediated reaction)

Persistent blood-streaked stools Visible blood in stools for >2 weeks despite milk-free diet → 2WW paediatric gastro (IBD, polyps, intussusception)

Anaphylaxis to cow's milk is rare (0.1% of children) but potentially fatal. IgE-mediated CMA can progress to anaphylaxis on subsequent exposures. Parents need adrenaline auto-injectors (2 devices) and emergency action plan. Delayed recognition = death.

FPIES (Food Protein-Induced Enterocolitis Syndrome) is non-IgE-mediated but presents with shock-like state — profound vomiting, lethargy, hypotension 2-4 hours post-milk exposure. Often misdiagnosed as sepsis or gastroenteritis. Requires IV fluids, sometimes steroids. Recurrence risk 100% on re-exposure until resolution (typically age 3-5 years).

Faltering growth is the most serious non-acute complication. Malnutrition in infancy causes irreversible neurodevelopmental harm. Weight crossing 2+ centile lines = red flag requiring same-day paediatric input for feeding assessment, nutritional rehabilitation.

Diagnose

History — Symptom pattern, timing, feeding history

Done

Take detailed feeding history focusing on symptom onset, timing relative to milk exposure, and response to avoidance.

Timing of symptoms

Immediate (<2 hours): IgE-mediated (urticaria, angioedema, wheeze, vomiting). Delayed (2 hours - 72 hours): Non-IgE-mediated (eczema, proctocolitis, reflux, colic). Both patterns: Mixed IgE/non-IgE.

Feeding history

Breastfed: CMA can occur via maternal diet (cow's milk proteins in breast milk). Formula-fed: Standard infant formula contains cow's milk protein. Weaning: Symptoms may start when yoghurt, cheese, cow's milk introduced. Age of onset: Typically <6 months.

Symptom diary

Request parent-completed food-symptom diary for 1-2 weeks. Record: all feeds/foods, symptom type, timing, severity (0-10). Bring to next appointment. Essential for establishing temporal relationship.

Gastrointestinal

Vomiting (immediate or delayed), diarrhoea, blood/mucus in stools, constipation (paradoxically), colic (inconsolable crying >3 hrs/day), reflux symptoms (back arching, possetting).

Skin

Atopic eczema (dry, itchy, erythematous patches flexures/face), urticaria (raised itchy wheals within 2 hours), angioedema (lip/facial swelling). Eczema alone does NOT diagnose CMA — trial needed.

Respiratory

Wheeze, chronic cough, nasal congestion (rare as sole manifestation). Caution: Respiratory symptoms alone rarely CMA — consider asthma, viral infections.

Family history

Atopy (eczema, asthma, allergic rhinitis, food allergies) in first-degree relatives increases CMA risk 3-fold. Ask specifically about parental/sibling allergies.

Response to avoidance

Key diagnostic feature: Did symptoms improve with cow's milk elimination? IgE-mediated: Improvement within 2-4 weeks. Non-IgE: Improvement within 2-6 weeks. No improvement: Reconsider diagnosis.

Timing distinguishes mechanism: IgE-mediated reactions occur within minutes to 2 hours (histamine release, mast cell degranulation). Non-IgE reactions are delayed (T-cell mediated, immune complex formation). Mixed presentations occur in 20% cases.

Symptom diary is diagnostic gold standard — establishes temporal relationship between milk exposure and symptoms. More reliable than retrospective recall. Parent-reported diaries have 85% sensitivity for identifying culprit foods in validated studies.

Over-diagnosis is rampant: 15% of parents believe their child has CMA, but only 2-3% actually have confirmed CMA. Symptoms attributed to CMA (colic, reflux, eczema) are common in infants regardless of diet. Response to elimination + challenge is essential to confirm diagnosis.

Diagnose

Classification — IgE-mediated vs Non-IgE-mediated

Done

Classify based on symptom pattern and timing. Determines investigation and management strategy.

IgE-mediated CMA

Features: Immediate onset (<2 hours), urticaria, angioedema, acute vomiting, wheeze, anaphylaxis. Prevalence: 0.5% infants. Investigation: Skin prick test or specific IgE blood test. Management: Strict avoidance, adrenaline auto-injector if severe. High risk anaphylaxis

Non-IgE-mediated CMA

Features: Delayed onset (>2 hours, up to 72 hours), eczema, proctocolitis (blood-streaked stools), reflux symptoms, chronic diarrhoea, colic. Prevalence: 2-3% infants. Investigation: Clinical diagnosis + elimination-reintroduction trial. Allergy tests negative. Lower risk

Mixed IgE/non-IgE

Features: Combination of immediate and delayed symptoms. Example: urticaria within 1 hour + worsening eczema over days. Prevalence: 20% of CMA cases. Management: Treat as IgE-mediated (higher risk). Allergy tests may be positive.

CMPI (proctocolitis)

Cow's Milk Protein-Induced Proctocolitis. Non-IgE subtype. Features: Blood-streaked mucousy stools in otherwise well infant age <6 months, normal growth. Breastfed babies most common. Prognosis: Excellent, resolves by age 12 months. Benign

FPIES

Food Protein-Induced Enterocolitis Syndrome. Rare non-IgE subtype. Features: Profuse vomiting 2-4 hours post-exposure, lethargy, pallor, shock-like state. No skin/respiratory symptoms. Allergy tests negative. Management: Strict avoidance until age 3-5 years. Medical emergency

FPIAP

Food Protein-Induced Allergic Proctitis. Synonymous with CMPI. Blood in stools, well infant, normal growth. Self-limiting, resolves age 12 months.

Classification drives management: IgE-mediated requires adrenaline auto-injector prescription, specialist allergy input, and annual review of tolerance. Non-IgE-mediated managed in primary care with elimination diet + home reintroduction. Misclassification = inappropriate treatment.

Proctocolitis (CMPI) is the most common non-IgE presentation — isolated blood-streaked stools in well breastfed infant. Benign, self-limiting. Do NOT over-investigate (colonoscopy unnecessary). Maternal cow's milk elimination trial sufficient. 95% resolve by 12 months.

FPIES is rare but serious — presents like septic shock (lethargy, pallor, hypotension) but is food-triggered. Delayed presentation (2-4 hours) means it's often missed. Requires IV fluids, observation. Allergy tests are negative (non-IgE mechanism), making diagnosis challenging. Only confirmed by re-challenge under medical supervision.

Diagnose

Examination — Growth, eczema severity, general wellbeing

Done

Focus on growth parameters, skin examination, and systemic wellbeing.

Growth parameters

Weight, length, head circumference plotted on centile charts (WHO 0-4 years, UK-WHO 4+ years). Faltering growth: Weight crossing down 2+ centile lines. Failure to thrive: Weight <2nd centile + poor weight gain. Document all measurements in PCHR (red book).

Skin examination

Eczema severity: Extent (% body surface area), distribution (flexures, face, trunk), signs of infection (weeping, crusting, pustules). Urticaria: Raised erythematous wheals (if present during consultation). Angioedema: Lip/facial swelling.

Abdominal exam

Palpate for masses (unlikely but exclude), assess for tenderness (unlikely in non-IgE CMA). Listen for bowel sounds (hyperactive in acute FPIES). Generally unremarkable in CMA.

General wellbeing

Alert and interactive? Lethargy, pallor, irritability may indicate systemic involvement. Hydration status: Mucous membranes, fontanelle (if open), urine output. Respiratory: Wheeze, stridor, increased work of breathing.

Nappy contents

If blood/mucus in stools reported, inspect nappy if brought or request photo for next appointment. Frank blood: Red streaks. Melaena: Black tarry stools (upper GI bleed). Mucousy: Thick clear/white mucus.

Development

Age-appropriate milestones (social smile 6 weeks, sitting 6 months, walking 12-18 months). Malnutrition causes developmental delay. Document in PCHR.

Growth monitoring is mandatory — faltering growth is the most serious complication of CMA. Malnutrition in first 2 years causes irreversible neurodevelopmental harm (reduced IQ, poor school performance, behavioral issues). Crossing 2+ centile lines = urgent paediatric dietitian referral.

Eczema alone does NOT diagnose CMA — 20% of infants have eczema, only 30% of those have food allergy. Moderate-severe eczema unresponsive to topical steroids warrants CMA trial, but most eczema improves with emollients + steroids alone.

Visual confirmation of blood in stools is important — parental reporting of "blood" can be mistaken (food dyes, urates in nappy, anal fissure from constipation). If persistent despite maternal cow's milk elimination, consider other causes (IBD, polyps, intussusception).

Diagnose

Investigations — Selective testing based on presentation

Done

IgE-mediated: allergy test. Non-IgE-mediated: clinical diagnosis + elimination trial. Do NOT over-investigate.

IgE-mediated — testing

Skin prick test (SPT): Gold standard, performed by allergy specialist. Wheal ≥3mm = positive. Specific IgE blood test: Alternative if SPT unavailable. Cow's milk IgE >0.35 kUA/L = positive. Do NOT order if no immediate symptoms — negative predictive value low for non-IgE CMA.

Non-IgE-mediated — NO testing

Allergy tests (SPT, specific IgE) are NEGATIVE in non-IgE CMA by definition. Diagnosis: Clinical (symptom pattern + response to elimination + positive reintroduction challenge). Testing misleads: Negative test does NOT exclude non-IgE CMA. Do not test

Elimination trial

Method: Eliminate ALL cow's milk protein (formula, maternal diet if breastfeeding) for 2-4 weeks (IgE) or 2-6 weeks (non-IgE). Improvement: Symptoms resolve/significantly improve. Proceed to: Supervised reintroduction challenge to confirm diagnosis.

Reintroduction challenge

When: After 2-6 weeks elimination IF symptoms improved. IgE-mediated: Hospital-supervised challenge (anaphylaxis risk). Non-IgE-mediated: Home challenge under GP guidance (low risk). Positive challenge: Symptoms recur within 2-4 weeks = CMA confirmed.

Bloods — rarely needed

FBC: If anaemia suspected (chronic blood loss in proctocolitis). Albumin: If severe malnutrition/malabsorption. NOT routine. Over-investigation causes anxiety.

Do NOT investigate

IgG testing (commercial "food intolerance" tests) — not validated, NOT recommended (NICE, BSACI). Patch testing — no role in CMA diagnosis. Endoscopy/colonoscopy — only if red flags (persistent GI bleeding despite milk-free diet, weight loss, IBD suspected).

Allergy tests only useful for IgE-mediated CMA — skin prick test has 90% sensitivity and 50% specificity. Positive test means 50% chance of clinical allergy (not 100%). Negative test in non-IgE CMA is expected and normal. Testing non-IgE patients generates false reassurance or unnecessary dietary restrictions.

Elimination-reintroduction is gold standard for non-IgE CMA. No blood test exists. Clinical diagnosis based on: (1) symptoms improve with elimination, (2) symptoms recur with reintroduction. If both criteria met = CMA confirmed. If symptoms do NOT improve with elimination = NOT CMA.

IgG food tests are scams — IgG antibodies to food proteins are NORMAL physiological response to dietary proteins, not pathological. NICE, BSACI, EAACI all recommend against IgG testing. Widely sold commercially but no evidence base. Causes unnecessary dietary restrictions and parental anxiety.

Refer

Referral Criteria — When to escalate

Done

Refer IgE-mediated CMA, faltering growth, severe symptoms, diagnostic uncertainty, or reintroduction failure.

999 / Same-day

Anaphylaxis. Severe faltering growth (weight <2nd centile, crossing 2+ lines). FPIES suspected (profuse vomiting + shock-like state). Dehydration. Persistent haematemesis/melaena.

Urgent allergy

IgE-mediated CMA suspected: Immediate reactions (urticaria, angioedema, wheeze) → allergy clinic for SPT, adrenaline prescription, action plan. Mixed IgE/non-IgE. Multiple food allergies. Severe eczema unresponsive to treatment.

Routine paediatrics

Non-IgE CMA with poor growth (even if not faltering) → dietitian input. No improvement after 6 weeks milk-free diet (reassess diagnosis). Breastfeeding mother struggling with elimination diet (dietitian support). Parent request/anxiety despite reassurance.

Dietitian

All CMA cases benefit from dietitian input for: nutritional adequacy assessment, calcium/vitamin D supplementation, weaning advice, formula selection, reintroduction planning. Essential if: Multiple food allergies, faltering growth, breastfeeding mother.

Primary care

Non-IgE CMA with: Mild symptoms, normal growth, straightforward elimination diet, clear response to milk-free trial. GP manages: extensively hydrolysed formula prescription, monitoring, home reintroduction at age 12 months, annual review.

IgE-mediated CMA requires allergy specialist input — adrenaline auto-injector prescription, emergency action plan, skin prick testing, management of anaphylaxis risk. Primary care cannot provide this level of specialist care. Annual review of tolerance with supervised challenges needed.

Dietitian input prevents malnutrition — cow's milk provides 50% of toddler's calcium, protein, and calories. Elimination without expert guidance risks rickets (vitamin D/calcium deficiency), protein-energy malnutrition, restricted growth. Dietitians assess nutritional adequacy, prescribe appropriate supplements, ensure balanced diet.

Non-IgE CMA can be managed in primary care if: diagnosis clear, growth normal, parents confident, single allergen. GP monitors growth, prescribes hypoallergenic formula, guides home reintroduction. Escalate if: multiple allergies, faltering growth, diagnostic uncertainty, parental anxiety high.

Treat

Milk Avoidance — Formula ladder and dietary substitution

Done

Eliminate cow's milk protein via maternal diet (breastfeeding) or hypoallergenic formula. Monitor growth closely.

Breastfed baby

Maternal cow's milk elimination First-line

Mother eliminates ALL dairy (milk, cheese, yoghurt, butter, cream, ice cream, chocolate). Continue breastfeeding. Calcium 1000 mg + Vitamin D 10 mcg daily for mother. Dietitian support essential.

Formula-fed baby — non-IgE

Extensively hydrolysed formula (EHF) First-line

Nutramigen, Similac Alimentum, Aptamil Pepti. Proteins broken into small peptides. Prescribe on FP10. Trial 2-6 weeks. Improves symptoms in 90% non-IgE CMA.

EHF intolerant / IgE-mediated severe

Amino acid formula (AAF) Second-line

Neocate, Alfamino, Nutramigen Puramino. Elemental (no intact proteins). For: EHF refusal, severe IgE CMA, FPIES, eosinophilic oesophagitis. Specialist prescribing.

Step 1Extensively Hydrolysed Formula (EHF) — Nutramigen (Mead Johnson), Similac Alimentum (Abbott), Aptamil Pepti (Danone). Prescribe on FP10 (free on NHS). Trial 2-6 weeks. Bitter taste — may refuse initially.

Step 2Amino Acid Formula (AAF) — If EHF refused or no improvement. Neocate, Alfamino, Nutramigen Puramino. Elemental, hypoallergenic. More expensive (£30-40/tin vs £15 EHF). Specialist input before switching.

Step 3Soya formula — AVOID if age <6 months (phytoestrogens). Use age >6 months if EHF/AAF refused. 50% cross-reactivity with CMA. Not first-line. SMA Wysoy, Cow & Gate Infasoy.

AlternativeOat/rice/coconut milk — NOT suitable as sole milk source age <1 year (nutritionally inadequate). For cooking/cereal only. Unsweetened, calcium-fortified versions. From age 1+ year as drink if CMA persistent.

Vitamin D + Calcium

All children on milk-free diet: Vitamin D 400 IU (10 mcg) daily. Calcium: EHF/AAF provide adequate calcium. If alternative milks used age 1+ years, ensure 350 mg calcium daily (fortified plant milks, green vegetables, tahini).

Weaning advice

Introduce solids age 6 months as usual. Avoid: Cow's milk, cheese, yoghurt, butter, cream, milk powder. Hidden milk: Bread, biscuits, cakes, ready meals (check labels). Safe: Meat, fish, fruit, vegetables, rice, pasta, lentils, eggs (if tolerated).

Label reading

Teach parents to check labels. Avoid if contains: Milk, casein, whey, lactose, butter, cream, ghee, curds. UK labelling law: Allergens in bold. App: "CMPA support" by British Dietetic Association.

Adrenaline auto-injector

IgE-mediated CMA only: Prescribe 2 adrenaline auto-injectors. EpiPen Jr 150 mcg (7.5-25 kg), EpiPen 300 mcg (>25 kg). Train parents: anterolateral thigh, hold 10 seconds. Emergency action plan. Call 999 after use.

Extensively hydrolysed formula (EHF) is first-line for non-IgE CMA — 90% effective. Proteins hydrolysed into small peptides unlikely to trigger immune response. Cheaper than amino acid formula (£15 vs £35/tin). Covered by NHS prescription (ACBS indication: "Proven Cow's Milk Allergy").

Amino acid formula (AAF) is reserved for: severe IgE CMA, EHF failure, eosinophilic disorders, FPIES. Completely elemental — no intact proteins. More expensive, worse taste (metallic), but 99% effective. Do not use AAF first-line — try EHF first unless specialist-directed.

Soya formula is NOT first-line — 10-14% of CMA infants also react to soya (cross-reactivity). Phytoestrogen content controversial (theoretical endocrine disruption). NICE recommends avoid <6 months. Use only if EHF/AAF refused or for cultural/religious reasons (after dietitian input).

Lifestyle

Parental Education — Safe feeding, label reading, eczema care

Done

Educate parents on milk avoidance, nutritional adequacy, emergency management, and prognosis.

Safe formula preparation EHF/AAF prepared same as standard formula: boil water, cool to 70°C, add powder, shake. Use within 2 hours. Discard unused formula after 24 hours. Never microwave (hot spots).

Label reading essential UK law requires allergens in BOLD on food labels. Avoid: milk, whey, casein, lactose, butter, cream, ghee, curds. Download "CMPA Support" app (British Dietetic Association) — scans barcodes, flags allergens.

Hidden milk sources Bread (milk powder), biscuits, cakes, chocolate, ready meals, processed meats (casein binders), crisps (milk flavouring). Always check labels even if product "looks" milk-free.

Breastfeeding support Mother must eliminate ALL dairy. Accidental exposure takes 2 weeks to clear from breast milk. Support groups: "Dairy Free for Baby UK" (Facebook), "Breastfeeding with CMPA" forum. Dietitian review essential.

Social situations Inform nursery, childminders, family members about strict milk avoidance. Provide safe snacks for parties. Teach child (age 2+ years) to say "I can't have milk". Medical alert bracelet for severe IgE CMA.

Eczema management CMA elimination improves eczema in 30% cases. Continue emollients 3-4x daily (Diprobase, Epaderm), topical steroids for flares (hydrocortisone 1% face, betamethasone 0.1% body). CMA elimination is NOT substitute for topical treatment.

Nutrition reassurance EHF/AAF provide complete nutrition — same calories, protein, calcium as standard formula. No additional supplements needed (except vitamin D 400 IU all children). Growth monitored regularly to ensure adequacy.

Prognosis counseling Non-IgE CMA: 90% outgrow by age 3 years, 50% by age 1. IgE-mediated: 50% outgrow by age 5, 80% by age 16. Annual review of tolerance via supervised challenges. Prognosis excellent — reassure parents CMA is not lifelong.

Prevent accidental exposure IgE-mediated CMA: carry adrenaline auto-injectors everywhere (2 devices). Train grandparents, nursery staff on use. Emergency action plan: IM adrenaline → call 999 → repeat dose after 5 mins if no improvement.

Weaning safely Start solids age 6 months as usual. Introduce high-allergen foods (egg, peanut, wheat, fish) unless allergist advises otherwise. Avoidance of allergens does NOT prevent allergies. Offer milk-free versions (soya yoghurt, oat milk on cereal).

Parental anxiety is major burden — CMA diagnosis causes significant stress (label reading, social restrictions, fear of reactions). Clear education reduces anxiety: EHF/AAF provides complete nutrition, CMA is usually outgrown, most reactions are mild. Reassurance is therapeutic.

Accidental exposures are common — 25% of CMA children have accidental exposure annually. Hidden milk in processed foods (bread, biscuits) is main culprit. Label reading education reduces exposure risk 70%. Apps like "CMPA Support" automate scanning — parents scan barcode, app flags allergens.

EHF/AAF nutritional adequacy is validated — formulas designed to meet 100% infant nutritional needs. No additional calcium or protein supplementation needed. Growth monitoring confirms adequacy. Parental concern about "missing out on nutrients" is unfounded — EHF provides same nutrition as standard formula.

Safety

Follow-Up — Growth monitoring and tolerance reintroduction

Done

Regular growth monitoring, review tolerance annually, plan milk reintroduction ladder.

2 weeks

After starting EHF/AAF: Phone review. Check symptom improvement (should see 50% reduction by 2 weeks). If no improvement → consider alternative diagnosis or step up to AAF. Check formula tolerance (taste, acceptance).

6 weeks

Face-to-face review: Measure weight, length, head circumference (plot on centile charts). Symptoms should be 80-90% improved. If not → reassess diagnosis. Review maternal diet if breastfeeding. Discuss weaning plan.

3-monthly (first year)

Growth monitoring: Weight, length, head circumference. Ensure adequate growth velocity. Dietitian review if growth concerns. Check vitamin D compliance. Adjust formula prescription volumes as infant grows.

Age 9-12 months

Milk ladder introduction: Start for non-IgE CMA with well-controlled symptoms and normal growth. Method: Gradual reintroduction of baked milk products (muffin, biscuit), then yoghurt, then cheese, then fresh milk. Duration: One step every 1-2 weeks. IgE-mediated: Hospital-supervised challenge.

Annual review

All CMA cases: Review tolerance via milk ladder progression or supervised challenge. Non-IgE: 50% outgrow by age 1, 90% by age 3. IgE-mediated: Repeat skin prick test or specific IgE to guide challenge timing. Most outgrow by age 5-16 years.

Safety-net 999

Anaphylaxis: Facial swelling, wheeze, stridor, collapse after milk exposure. FPIES reaction: Profuse vomiting, lethargy, pallor 2-4 hours post-exposure. Severe dehydration.

Safety-net Same-day GP

No symptom improvement after 6 weeks milk-free diet. Faltering growth (crossing centile lines). Persistent blood in stools despite maternal milk elimination. New concerning symptoms (vomiting, lethargy, rash).

Re-refer if

Multiple food allergies develop (egg, soya, wheat). Failure to thrive despite adequate formula. Severe eczema unresponsive to treatment. IgE CMA reactions worsening (escalating severity). Parent struggling with dietary restrictions (dietitian + psychology input).

Growth monitoring is mandatory — most important outcome measure. Faltering growth indicates inadequate nutrition or incorrect diagnosis. Infants on EHF/AAF should grow normally (same velocity as formula-fed peers). Crossing centile lines down = urgent dietitian referral.

Milk ladder is evidence-based tool for gradually reintroducing cow's milk in non-IgE CMA. Baked milk is least allergenic (heat denatures proteins), followed by fermented (yoghurt), then fresh milk. Sequential introduction allows immune tolerance induction. 80% of non-IgE CMA children tolerate baked milk by age 1 year.

Annual tolerance review prevents unnecessary prolonged avoidance. Many children outgrow CMA but remain on milk-free diet due to inertia. Regular challenges identify tolerance development. Delayed reintroduction increases risk of persistent allergy (immune system "forgets" how to tolerate milk).