DPCP Dilution Protocol for Alopecia Areata
Begin with initial sensitization using 2% DPCP solution applied to a small area of the scalp, then after 2 weeks start treatment at 0.001% concentration with weekly applications, gradually increasing the concentration until a mild dermatitis reaction is achieved. 1
Initial Sensitization Phase
- Apply 2% DPCP solution to a small area of the scalp as the first step to sensitize the patient 1
- Wait 2 weeks before beginning the treatment phase 1
- An alternative modified protocol uses 0.1% DPCP for sensitization, which may result in fewer adverse effects while maintaining efficacy 2
Treatment Phase Dilution Protocol
- Start treatment at 0.001% DPCP concentration applied to the scalp 1
- Apply weekly, increasing the concentration at each treatment session 1
- The target is to achieve a mild dermatitis reaction (erythema, itching, scaling) that lasts approximately 48 hours 1, 3
- Continue increasing concentration until this therapeutic endpoint is reached 1
Some protocols report starting at even lower concentrations (0.000001%) and titrating up more gradually, which may be appropriate for patients with sensitive skin 4. The modified protocol starting at 0.01% after sensitization with 0.1% has shown favorable results with 66% response rate and fewer severe adverse effects 2.
Unilateral vs. Bilateral Treatment Strategy
- Consider treating one side of the scalp initially to distinguish treatment response from spontaneous recovery 1
- Once hair regrowth is observed on the treated side, extend treatment to both sides of the scalp 1
- In patients with severe long-standing alopecia where spontaneous recovery is unlikely, this precaution is unnecessary and bilateral treatment can begin immediately 1
Critical Storage and Application Requirements
- DPCP is degraded by light and must be stored in the dark 1
- Patients must wear a hat or wig for 24 hours following application to prevent photodegradation 1
- Solutions should be prepared in acetone as the vehicle 5
- Maximum concentration used is typically 2% 5
Expected Response and Maintenance
- Initial response typically occurs at 3-4 months after starting treatment 3
- Maximum response is usually achieved by 6 months, though some patients may require up to 32 months of treatment for optimal results 1
- Once maximum response is achieved, reduce the frequency of treatment 1
- If complete regrowth occurs, treatment can be discontinued, though relapses occur in approximately 50-62% of patients 1, 5
Safety Precautions for Handlers
- All handlers (pharmacy, medical, nursing staff) must wear gloves and aprons to avoid inadvertent sensitization 1
- Great care must be taken to prevent contact with family members 1
- DPCP should not be used in pregnant women or women intending to become pregnant 1
- Batches should be screened for mutagenic contaminants by the supplier 1
Common Adverse Effects to Monitor
- Occipital and/or cervical lymphadenopathy occurs in most patients (40.7% in one series) but is usually temporary 1, 5
- Severe dermatitis can be minimized by careful concentration titration 1
- In patients with racially pigmented skin, warn about risk of cosmetically disabling hyper- or hypopigmentation including vitiligo before starting treatment 1
- Contact dermatitis of face or neck may occur but typically resolves with topical corticosteroids within 7 days 3
Efficacy Expectations
- Overall response rates range from 50-83%, with complete regrowth in 22-48% of patients 1, 6, 5, 4, 3
- Patients with extensive hair loss (alopecia totalis/universalis) have lower response rates of approximately 17% 1
- Poor prognostic factors include: nail changes, early onset, positive family history, atopy, and longer duration of disease 1, 4